Starting device for electric motors



R. KNAPP April 13, 1937.

STARTING DEVICE FOR ELECTRIC MOTORS Filed Oct. 23, 1956 INVENToR RaYNoNDKNAPP ATTORNEY Patented Apr. 13, 1937 UNIED 'Z (Claims.

This invention relates to improvements in a starting device for electricmotors and has for an object the provision of a starting deviceparticularly adapted to small motors such as used in motor driven toolswherein the starting mechanism must be small, simple and cheap tomanufacture.

Another object of the invention is to provide a device of the characterdescribed particularly suited for use in connection with motors used inshaving devices such as lthat shown and described in the co-pendingapplication, Serial Number 106,527 led Oct. 20, 1936, entitledImprovements in shaving devices and motors therefor.

A further object is to provide a starting device of the class describedconstituting an impulse starting mechanism adapted to be mechanicallyactuated by the insertion of the connection plug into the device.

Other objects and advantages will become apparent during the course ofthe following specification in connection with the accompanying drawingin which:

Figure 1 is a vertical sectional view through the center of the deviceembodying the invention;

Figure 2 is arvertical cross-sectional view of the device shown inFigure 1 on the line 2 2 thereof, the casing on the right, Figure l,being broken away to show the interior parts;

Figure 3 is a sectional view of the device shown in Figure 2 showing thestarting mechanism in two different positions and showing a connectingplug for use with the device; and

Figure 4 is a cross-sectional View on the line 4 4, Figure 2.

The numeral l0 denotes a casing forming a handle in which an electricmotor of any suitable A. C.D. C. construction, such as that shown in theaforesaid co-pending application, is mounted and enclosed. This motorhas a rotor il and a shaft I2 therefor, said shaft being supported inplates I3, I 4 so that said rotor may revolve between the poles l5, I 6of a eld structure hereinafter briey described. A lever i1 is supportedon a stud screw i8 mounted in the casing i0; the lower end of this leverbeing forked and engaging a cam (not shown) on the shaft l2 and thelever is oscillated by the rotation of this cam.

The upper end of lever I1 is in operative engagement with the cutter bari9 so as to oscillate the same below the slotted cutter plate 20 mountedon the head 2l secured tothe casing l0. The bar is a tool and the plateis in cooperative working relationship thereto. Hair (Cl. W32-m36)entering the slots in the cutter plate will be cut or sheared by theaction ci the cutter har in the usual manner.

The field structure has a core portion 22 supporting a winding orwindings 23 for energizing 5 the field structure. An interruptermechanism generally indicated at i251 is provided to cooperate with theiield Winding to cause the rotor il to revolve when current is appliedto the device via the circuit terminals 25, 26 which may be in the 10form of pins, as shown, mounted in a recess or socket 2l within the bodyof the casing or formed partly in the casing l0 and by the cover or capthereof 28, and preferably located at the bottom of the casing, asshown. M

it will be understood that the construction of the motor and the shavinghead per se, the latter being that portion of the device shown above theline A-A, Figure l, can be varied within wide limits; these may be ofthe construction 20 shown in the aforesaid co-pending application andthe details of construction may be varied within wide limits as thesepartsand the particular shaving device herein shown and described aremerely by way of .illustrating the 25 starting device applied to themotor and constituting this invention. However, some of the specificdetails of the new combination of a shaving device having an automaticstarting means for the motor are also claimed herein, the start- 30 ingdevice herein described is particularly suited to starting motors inshaving devices but is not limited to use therewith. It may be appliedto motors used for any purpose.

This starting device includes a reciprocating 35 arm 29 connected at itslower end to the plunger 30 which is loosely supported to slide in theplate 3l supported in the casing, said plate being preferably ofinsulating material and supporting the motor terminals 25, 26. The arm29 is 40 further supported in operative position by a bracket 32 mountedon plate M or on any other lsuitable support. This plate has a slot 33therein which permits lateral movement of the arm 29 therein aspresently described. 45

The hole in the plate 3l through which the plunger projects, is madewith rounded edges so that the plunger moves from side to side slightly,as it follows the movement of the arm 29 to which it is attached, orwith which it is an integral part. 50 The arm 29 therefore floats in itssupports 3l and 32 and is free to move laterally as well as reciprocatetherein, the lateral movement being very limited at the bottom end.

The arm 29 is connected at any suitable point, 55

such as at 34, with a spring anchored to the eld structure of the motoror at any other suitable point and said spring tends to yieldingly holdsaid arm in the position shown in Figure 2 and Figure 4 and in solidlines in Figure 3, with its plunger end 30 extending freely into therecess 21, the downward movement being stopped by means such as ashoulder 30a on the pin 3D or the turned over edge of 29.

The upper end of arm 29 is provided with engaging means such as a claw36 adapted to engage suitable rotatable means such as a toothed wheel 31mounted on the motor shaft i2 when the plunger 30 is pressed inwardly.

Motors of the type described often require manual starting, some meansof mechanically giving the motor armature or rotor an impulse to close apair of interrupter contacts, and to accomplish this with the mechanismjust described, the plunger 30 is pressed inwardly (current beingconnected to terminals 25, 26). This moves arm 29 upwards from theposition shown in Figure 2 and the claw 36 engages the teeth on wheel 31and rotates the same thereby rotating the shaft l2 and revolving therotor II.

The claw is held in engagement with wheel 31 by the spring 35, but asthe arm and plunger are free to move laterally in slot 33 and plate 3l,the claw will ride over the wheel 31 as shown in dot and dash lines,Figure 3, while turning the same and nally the arm and claw will come torest with the claw above and out of engagement with the wheel 31 asshown in solid lines Figure 3. The plunger 3D should then be held allthe way in, in any suitable manner, such s by the connecting plug aspresently described.

If the plunger is released, the arm 29 will be retracted by the spring35 from the position shown in Figure 3 to that shown in Figure 2, theclaw riding over the teeth in Wheel 31, the arm 29 and plunger 30 beingfree to move laterally as just described to permit its free return tonormal position.

The foregoing starting mechanism forms an impulse starting device for amotor and the preferred method of operating the plunger 30 is shown inFigure 3 wherein a connecting or attachment plug 38 is shown, theinsulating body of which is adapted to t within the recess 21 so thatthe plug Will extend therein as shown in dot and dash lines at 39,Figure 3. This plug has a solid portion 4D adapted to contact with theplunger 30 and force the same inwardly, thereby turning the rotor toclose a pair of interrupter contacts, while the plug is being pushed onits way into the recess or socket 21 and after, the live socket contacts4I, 42 have made contact with the motor circuit terminals or contactpins 25, 26. In this way the motor is started.

When plug 36 is withdrawn, the circuit is broken so that there is nocurrent on the motor. The plunger 30 is released when the plug is whollywithdrawn which permits the starting mechanism to return to normal inposition for another starting operation.

As the sockets 4l, 42 have their outer ends below the outer surface ofthe body of the plug, short circuits cannot arise by reason of placingthe plug with its end 40 against oonducting surfaces.

If desired, the terminals 25, 26 may project freely from the casingtogether with the plunger 30 and the connecting plug may t over theseterminals and be frictionally held in place thereby, while it operatesto press the plunger inward as rst described, the socket 21 beingomitted.

There is a peculiar cooperative relationship between the startingdevice, the main subject of this application, and an electrically driventool, such as the motor driven razor herein described by way ofillustration.

This relationship arises mainly from the fact that such electric razorsare commonly used in the bathroom where they are subject to an une dueamount of moisture.

Heretofore such razors have necessarily had a slot or opening in the'casing in which an arm or button was slidable, or some member having arim corresponding to the wheel 31 shown in this application projectingfrom the casing in order to be moved by the finger to start the motor.

All such arrangements permit the ingress of hair, soapsuds and the liketo the motor parts and the instant invention eliminates possibletroubles from these Sources.

Such electric razors in the past have commonly had the connecting cordpermanently connected to the razor, the free end of the cord beingequipped with the usual attachment cord for insertion in the socket.Such arrangements are objectionable because the cord, if of anyappreciable length, is much more bulky than the razor itself and isdiicult to put away in the small space commonly available in medicineclosets and the like where such razors are kept..

In connection with prior art razors having pin terminals thereon so thatthe cord connects directly thereto, the plug could often be inserted inthe razor and the razor would fail to start and if the user forgot topush the starting button but laid the razor down for any reason for awhile, the motor would get very hot.

By the improved arrangement herein described, the mere act of insertingthe plug in the razor automatically starts the same and the act ofdisconnecting the plug not only disconnects the razor from the source ofcurrent but automatically restores the starting mechanism to a positionwhere it is again ready for operation and it will be readily seen thatthis invention eliminates the possibility of connecting the razor to asource of current and then forgetting to start the same.

Although the invention has been described in connection with the specicdetails of preferred embodiments thereof, it must be understood thatsuch details are not intended to be limitative of the invention exceptinsofar as set forth in the accompanying claims.

What is claimed is:

l. In combination, a motor having a winding and a rotor, rotatable meansconnected to said rotor, an arm adapted to engage said means, a recessedcasing enclosing all said parts, means connected to said arm andextending into said recess adapted when pushed inwardly to cause saidarm to engage said means to rotate said rotor thereby, and terminalsconnected to said winding and projecting into said recess adjacent themeans connected to the arm for connection to an attachment plug from asource of current for operating said motor, whereby movement of the pluginto position on the terminals pushes the arm inwardly and rotates therotor.

2. In combination, a motor having a Winding and a rotor, rotatable meansconnected to said rotor, an arm adapted to engage said means, a.

recessed vcasing enclosing all said parts, means connected to saidv armand extending into said recess adapted when pushed inwardly to causesaid arm to engage said means to rotate said rotor thereby, terminalsconnected to said winding and projecting into said recess for connectionto a source of current for operating said motor, and an attachment plugtting into said recess and having a surface adapted to engage s aid armto engage said means to rotate said while said plug is being inserted insaid recess, said plug having members adapted to contact with saidterminals to supply current thereto when said plug is in said recess.-

3. In combination, a motor driven device, a casing therefor having asocket therein, terminals for said motor located within said socket, astarting device for said motor, means connected to socket and adaptedwhen pressed inwardly to mechanically start said motor, and meansadapted to t into said socket comprising an attachment plug adapted asit enters said socket to push said means, said plug carrying contactsadapted to connect with said terminals.

4. In combination, an electric motor having circuit terminals, animpulse `starting device therefor having a, plunger closely adjacentsaid terminals, and means comprising an attachment plug adapted t'oactuate said plunger to start said motor and simultaneously connect asupply circuit to said terminals.

CERTIFICATE OF CORRECTION.4

Patent' No.4 2,077,330.

5. The combination as claimed in claim 4 where said motor has a casinghaving a socket therein and said terminals and plunger are locatedwithin said socket and said plug is adapted to flt said socket andcooperate with said plunger and terminals for the purposes set forth.

6. In combination, a motor having a rotor and shaft, a toothed wheel onsaid shaft, an arm supported on said motor and having means adapted toengage and turn said wheel when said arm is reciprocated in a planeperpendicular to said shaft, a support for said arm having a slotpermitting lateral motion of said arm therein, and means tending tomaintain said arm normally out of contact with said wheel.

7. An electric tool comprising a casing, a tool supported thereon, a.motor enclosed thereby and A connected to said tool, a mechanicalstarting desaid starting device and extending within said vice mountedwithin said casing. a plunger extending through the bottom of saidcasing and adapted when manually operated to cause said starting deviceto start said motor, and motor circuit terminals extending through thebottom of said casing spaced apart and adjacent said plunger, saidplunger and motor terminals being mounted on a plate secured to saidcasing, said plunger and terminals being partly surrounded bysaid casingwhereby contact with the sides of said terminals is prevented.

RAYMOND KNAPP.

RAYMOND KNAPP.

April 15, 1937.

It is hereby certified that error appears i-n the printed specificationof the above numbered patent requiring correction-as follows: firstcolumn, line 10,. claim 2,. for the words "arm to engage said means Page3,

to rotate said"l read second means to push the same inwardly; and thatthe said Letters Patent should be read with this correction therein thatthe same may conform to the record of the case in the Patent Office.

Signed and sealed this 1st vclay of June, A. D. 195'?.

(Seial) Henry Van Arsdale Acting Commissioner of Patents.

